Lighted push button starting switch



June 19, 1962 w. DlETRlCH ETAL 3,040,142

LIGHTED PUSH BUTTON STARTING SWITCH Filed Oct. 22, 1959 2 Sheets-Sheet 2 2 L STOP /8 L u'ann STOP 50 it F/G. 9

//7 van/0m W P01] GU/lj Z MC Wa/fer L. D/e/n'ch By f/ve/r af/omeys Filed Oct. 22, 1959, Ser. No. 848,052 2 C im .(C -8 This invention relates to electric push button switches such as are commonly used to start electromagnetic switches that are located at a point usually remote from the starting switch. -More particularly, the invention relates to a push button starting switch having a pilot light and provision for testing the pilot light by manipulation of the button. I

It is an object of the invention to provide an improved push button switch capable of operating an electromagnetic contactor and having a pilot light associated therewith and having provision for testing the pilot light at will without pressing the'button.

Another object is to providean improved push button switch of the above-mentioned type in which the pilot light can betested by turning a button without depressing it.

Another object is to provide an improved push button switch ofthe above-mentioned type in which depression of the push button automatically tests the pilot light during the first small fraction of its depressive movement.

Another object is to provide an improved push button switch of the above-mentioned type'having provision to prevent rotary movement to test except when the button isin normal unpressed position or, in other words, to prevent rotation of the button to test while the button is depressed.

Another object of the invention is to provide an improved push button switch of the above-mentioned type having provision to prevent depression of the push button while" it is in turn-to-test position.

Another object of the invention is to provide an improved push button switch of the above-mentioned type having an auxiliary contact operable by either fractional depression or by rotation of the push button to test the condition of the pilot light.

Other objects and advantages of the invention will become apparent as it is described in connection with the accompanying drawings.

In the drawings:

FIGS. 1, 2 and 3 are side elevation views, partly in section and partlybroken away, to show three different positions of the switch, specifically the normal, the turnedfor-test, and the fully depressed condition of the button.

FIG. 4 is a side elevational section view through a switch. embodying the invention, the section being taken along line 4--+4 of FIG. 5.

FIG. -5qisa transverse sectionview taking along line 55 of {FIG. 4 with the spring and pilot light removed. .FIG. 6 is a detailed perspective view of the contact actuating member or cam ring used in the invention. "FIGS. 7,98,..9 and 10 are circuit diagrams showing the difierent positions of the switch .and the circuits completed when the magnetic contactoris open, when the pilot light is being tested, when the magnetic contactor is being closed and when the contactor is closed and the button has returned to unpressed condition.

Referring to the drawings, the invention comprises es- .sentiallya combination of three main assemblies: a switch ofspecial constructionand function, a pilot light .and

stepdown transformer. All are mounted on a base made of molded insulatingmaterial divided=from top to. bottom (as .viewed in. the-draw ings), to form two cooperating intertitting parts 10 and 12.

3,040,142 Patented June 19 1962 ice The transformer -T, which provides low voltage for the pilot light, is mounted in the base part 12 while the switch contact mechanism is mounted in the part '10. The pilot light and the actuating portion of the switch are mounted on top of the base parts 10 and 12 and upon a casting 20, as will be described.

The whole device is adapted to be mounted in an opening in a panel board (not shown) or elsewhere by insertion of an externally screw-threaded neck 14m of a main metallic mounting member 14 having at its inner end a radially extending flange 14 which may be square with rounded corners, as shown.

Against the inner surface of the flange 14]- is secured a similarly shaped plate 20 by screws 15 (FIGURES); and the plate 20 is in turn secured to the base parts 10 and 12 by long bolts (not shown) passing from the bottom of the base up through the base and threading into holes in the mounting plate 20.

Mounted on the plate 2 0 at its center is a conventional electric light socket 16 of bayonet or other type for a miniature electric light bulb 18. Also mounted on the plate 20 between the socket 16 and the wall of the neck 1411 of the main mounting member 14 is a'sleeve-boss 22. For actuating the switch contacts, as will presently be described, a cylindrical pin 24 slides in the sleeve-boss 22.

For actuating the pin 24, a circular contact-actuating member 30 is slidably received within the neck Mn and is biased upwardly or outwardly by a coiled compression spring 39, the lower end of which presses upon and is anchored to the main mounting plate 20 while the upper end presses against the contact-actuating member 30 and has its extremity anchored in a groove formed in the periphcry of the contact-actuating member, as illustrated in FIG- URE 5. An overhanging internal lip or flange on the neck 14:1 stops the contact-actuating member 30 at the top of its travel.

Surrounding the light bulb 18 and movable axially with respect thereto is a transparent or translucent cylindrical hollow push button 34 preferably made from synthetic plastic material. The lower end of the push button is secured by screw-threaded engagement to a neck 32 upstanding from the contact-actuating member 30 so that the button and contact-actuating member move as a unit when the button is pushed inward against the force of the spring 39. The inward travel of the button is stopped when the inner face of the member 30 abuts the top of the sleeve-boss 22.

Not only is the pin 24 movable by reciprocation of the button, but also to a lesser extent by rotation of the button by the following means.

On the bottom or inner face of the contact-actuating member 30 is molded an arcuate helical cam surface 36 (see FIGURES 2, 5 and 6) of about extent rising from the radial face of the member 30. This cam is of such radius from the axis of the push button and member 30 as to override the pin 24. As the member Gdand push button 34 are manually turned, first the low end and then the high portion ofthe cam 36 pass over the pin and the pin is gradually depressed to the extent of the height of the cam. This causes separation of one switch contact from another, as will hereinafter more fully appear.

The turning of the push button ,winds up the spring 39 due to anchoring of both ends of the spring as above described. Hence, on releaseof the manual turning force, the button returns to initial position allowing the pin 24 to rise to its normal elevated position.

In order to prevent depression of the button when it is rotated, an arcuate rib 38 of about 90 extent is formed on and perpendicular to the inner radially extending surface of the contact-actuating member '30 at a radius to overlie the margin of the sleeve-boss 22 outside the pin '3 24. This rib terminates in ends perpendicular to the radial face of member and has a curved edge adapted to be moved over the sleeve-boss. Thus, when the button and contact-actuating member are turned and an effort is simultaneously made to depress the button, the curved edge of the rib 38 will abut the top outer margin of the sleeveboss and prevent depressive movement of the button at all turned positions of the button.

The rib 38 also serves to prevent rotation of the button after the button has been depressed because in depressed position, the perpendicular end surface 38c, i.e. the end surface parallel to the button axis, will abut the side of the sleeve-boss and frustrate the effort to turn the button.

To limit rotation of the button to about 90, a peripheral notch 3011 of about 90 extent is formed in the contact-actuating member diametrically opposite the rib 38; and a rectilinear fin 14s parallel to the axis of the button and radially extending inward from the inner peripheral surface of the main mounting member 14 extends into the notch 3021.

The switch actuated by the button 34 and pin 24 consists of a pair of conventional fixed switch contacts A and B (herein referred to as upper contacts) on conventional wire terminals 52 and 54, respectively, and a pair of contacts B and E (herein referred to as lower contacts) on wire terminals 56 and 58, respectively, located in align ment with the terminals and contacts A and B and D and E, respectively.

The bridging contact 50, having contact buttons on both its upper and lower surfaces at each end, is located between the upper and lower fixed contact pairs and is loosely carried on a connecting rod 42 which is between and rigidly connects spaced insulating blocks and 44 of a contact-operating slide. This connecting rod may be non-circu1ar in cross-section to prevent turning of the bridging contact thereon. The blocks 40 and 44 are preferably rectangular and slide in a guideway 10g formed in the base part 10. The contact-operating slide is biased upward by a coiled compression spring 46 in the lower end of the guideway 10g. One end of the spring rests on an anchor plate or plug insert in the end of the guideway while the other end of the spring presses against the block 44 of the slide, thus causing the opposite end of the block 40 to abut against and be stopped by the socket mounting plate 20, as shown in FIGURES 1 and 4.

The bridging contact is biased toward the contacts A and B by a coiled compression spring 48 on the connecting rod 42, one end resting on the block 44 while the other presses against the bridging contact 50. As shown in FIGURE 1, the contact-operating slide is normally held in upper most position by the spring 46 while the bridging contact 50 is held in engagement with the contacts A and B by the spring 48.

In order to tilt the bridging contact and to cause its disengagement from the fixed contact A while the bridging contact remains in contact with the fixed contact B, and in order to connect the fixed contact B with the fixed contact D, a lug 53 is formed on the midportion of the bridging contact 50 alongside of the aperture therein through which the connecting rod 42 passes. Thus, when the contactoperating slide moves downward as a result of the depression of the button 34, the block 40 will exert an unbalanced pressure on the bridging contact 50 which causes it to tilt from the position shown in FIGURE 1 to a position somewhat similar to that shown in FIGURE 2. As shown in FIGURE 2, the bridging contact has been tilted due to the downward movement of the block 40 resulting from turning of the button 34 and the camming action of the the cam 36 on the pin 24.

Although the foregoing tilting will break thecircuit between the fixed contacts A and B by separating the bridging contact from the fixed contact A, it is desired when this tilting occurs to make a connection between the fixed contact B and the fixed contact D for reasons as will hereinafter more fully appear. Moreover, it is very desirable that the connection to fixed contact D shall be made be fore that end of rigid bridging contact, which separates first from fixed contact A, comes into engagement with fixed contact D. This is desirable because immediately upon the rigid bridging contact engaging contact D, the continued movement of the lug 53 and block 40 will cause the bridging contact to pivot about that point of engagement, immediately separating the other end of the bridging contact from fixed contact B. Thus, on turning the button 34 there is a need for lost motion after contact has been established between fixed contacts B and D to ensure retention of engagement between the bridging contact and contact B.

In order to accomplish this, an oblique angled auxil iliary contact 51, made preferably by bending a strip of thin sheet metal, is afiixed at one end adjacent to the contact button further from the lug 51 or, in other words, adjacent the button at the end of the bridging contact which remains in engagement with the fixed contact B during said tilting. The opposite end of this auxiliary spring contact overlies the fixed contact D alongside of the button thereon, but is normally separated from the fixed contact D as shown in FIGURE 1, i.e. when the bridging contact is in uppermost position and in engagement with both the fixed contacts A and B. However, on tilting movement of the bridging contact, the auxiliary contact 51 engages the fixed contact D, completing the circuit between the fixed contacts B and D.

Upon engagement of the auxiliary contact 51 with lower fixed contact D, the auxiliary contact 51 will bend and become stressed and will exert a small force on the end of the bridging contact at its point of attachment to the bridging contact. This small force acts to press the bridging contact toward fixed contact B, thus increasing the amount of force required to cause separatiton from contact B. During the first portion of the movement of bridging contact 50 as the button is pushed, all the applied force is used in overcoming the force of the compression springs 46 and 48; and the bridging contact pivots about its point of engagement with fixed contact B.

a On full depression of the push button 34, the bridging contact will move down into the position shown in FIG- URE 3. During the movement to this position, the end of the bridging contact which has first separated from the fixed contact A will come into engagement with the fixed contact D. Immediately, the bridging contact will start tilting in the opposite direction until its opposite end comes into engagement with the fixed contact E.

In use, the switch may be connected in circuit as shown in FIGURES 7-10. The leads, from the secondary winding of the transformer T are connected to the base and shell contacts of the electric light socket permanently. One end of the primary winding of the transformer T is connected to power line L and the other to terminal 54 of the fixed switch contact B.

The other power line L is connected through a conventional stop switch both to the fixed switch contact D and to one of the usual holding-contacts of a conventional electromagnetic contactor. The other holdingcontact of the contactor is connected both to the fixed switch contact E and to one end of the holding coil MC of the contactor. The opposite end of this coil is connected to the power line L A fixed shunt s connects fixed switch contacts A and E.

The normal open-circuit condition is illustrated in FIGURE 7 in which the switch parts occupy the positions as shown in FIGURE 1.

To test the condition of the pilot light bulb 18, the button 34 is rotated without depression thereof because, on rotation, depression is prevented by the rib 38 abutting the top of the sleeve-boss 22 as previously described and as shown in FIGURE 2. The rotation of the push button depresses the pin 24 slightly by action of the cam 36; and the pin 24 depresses the contact-operating slide,

whereupon the slide block 40, pushing on leg 53 of the bridging contact, tilts the bridging contact as previously described. This test condition is shown in FIGURE 8 and the switch parts occupy the positions as shown in FIGURE 2.

As shown in FIGURE 2, tilting ofthe bridging contact causes the bridging contact to separate from the fixed switch contact A and auxiliary contact 51 to engage the fixed contact D, thereby connecting it to fixed contact B. The circuit is completed thereby from the line L through the auxiliary contact 51 and transformer to the line L and the pilot lamp lights. The same circuit connections are completed when the button is not rotated, but is fractionally depressed.

When the push button is fully depressed, the circuit conditions are as illustrated in FIGURE 9 in which the switch parts occupy the positions shown in FIGURE 3. The circuit is established from line L through the normally closed stop switch and then through contacts D and E, bridged by bridging contact 50, and through the holding coil MC of the electromagnetic contactor to line L Closing of the contactor causes closing of its holding contacts H which are in shunt with fixed contacts B and E. The pilot light is momentarily not lit.

Now when the push button is released, the electromagnetic contactor remains closed because the holding contacts H remain closed. And, the rising of bridging switch contact "50 to its initial position has closed the circuit between contacts A and B. This establishes the circuit from line L through the transformer and the shunt s to the fixed contact E and holding contacts H and stop switch to the line L, and the pilot lamp glows.

Opening the stop switch returns the circuit to the condition illustrated in FIGURE 1 because of the opening of the holding contacts H and energizing coil MC.

The pilot light-18 will then go out.

It is desirable to be able to test the condition of the pilot light without depressing the push button and running the risk of pressing it too far, thereby closing the electromagnetic contactor. This is accomplished by reason of the interlocking of the push button and contact- -actuating-member .30 with the sleeve-boss 22.

From the foregoing, it will be apparent that the switch mechanism and circuit conditions provided by this invention enable the testing of the pilot light without causingclosure ofthe electromagnetic contactor and without the danger of the contactor being closed accidentally during such testing. The invention also provides for automatically testing the pilot light preliminary to the energization of-the electromagnetic contactor when the first fractional depressive movement of the push button occurs.

If the pilot light does not flash on and then off while the push button is being depressed, the operator will know that the pilot light is not operative and, hence, if the light does not light after the normal actions in starting theelectromagnetic contactor have been completed, the operator will know that the pilot light circuit is not operative and he will not have a signal to tell whether the magnetic switch has. closed. He may then test thepilot light by turning the push button without efaforton .the existing condition of the magnetic contactor. -;If the .test shows that the pilotlight is operative, but

the light .does not remain on even though the normal operations, in energizing the electromagnetic contactor, have been completed, the operator will know that the electromagnetic contactor or some other portion of its circuit is at fault.

Many modifications within the scope of the invention and other uses in addition to that of the preferred embodiment illustrated and described will occur to those skilled in the art in circuit arrangements using all or only some of the contacts, in which the contacts may all or only in part be connected to wire conductors in the circuit.

Therefore, the invention is not limited to the specific form and embodiment illustrated.

What is claimed is:

1. In an electric switch, a pair of fixed contacts, a second pair of fixed contacts, movable bridging contact means adapted to bridge said first pair or second pair, operating means rotatable about an axis to move said bridging contact means, said operating means also being movable rectilinearly parallel to said axis from a first position in which said bridging contact means bridges said first pair into a second position bridging said second pair, means to cause said bridging contact means to disengage one of said first pair of fixed contacts on fractional movement of said bridging contact means from said first position to said second position and to engage a contact of said second pair While remaining engaged with the other fixed contact of said first pair.

2. In an electric switch, a pair of fixed contacts, a second pair of fixed contacts, movable bridging contact means adapted to bridge the first pair or the second pair, operating means rotatable about an axis to move said bridging contact means, said operating means also being movable rectilinearly parallel to said axis from a first position in which said bridging contact means bridges said first pair into a second position bridging said second pair, and means operable by rotation of said operating means to cause said bridging contact means to be tilted by said contact-operating member causing said bridging contact means to-disengage one contactof said first pair and to engage one of said second pair of fixed contacts while remaining engaged with the other fixed contact of said first pair.

3. In an electric switch, a pair of fixed contacts, a second pair of fixed contacts, movable bridging contact means adapted to bridge said first pair or second pair, operating means to move said bridging contact means from a first position bridging said first pair into a second position bridging said second pair, means to cause said bridging contact means to disengage one of said first pair of fixed contacts on fractional movement of said bridging contact means from said first position to said second position, said bridging contact means including an auxiliary contact which engages a contact of said second pair during said fractional movement while said bridging contact means remains engaged with the other fixed contact of said first pair.

4. A switches claimed in claim 3 in which said auxiliary contact upon engaging said one contact of said second pair exerts a force tending to hold the opposite end of said bridging contact in engagement with said other contact of said first pair.

5. In an electric-switch, a pair of fixed contacts, a second pair of fixed contacts, movable bridging contact means adapted to bridge said first pair or second pair, operating mcans to move said bridging contact means from a first bridging contact means including a flexible metal auxiliary contact connected at one end to said bridging con tact means and free at its other end which engages a contact of said second pair during said fractional movement while said bridging contact means remains engaged with the other fixed contact of said first pair, said auxiliary contact folding under said bridging contact means upon the latter coming into said second position.

6. An electric switch as claimed in claim 1 having means to prevent rectilinear movement of the operating means when the latter is rotated.

7. An electric switch as claimed in claim 6 having means to prevent rotation of said operating means when the latter is pushed.

8. An electric switch as claimed in claim 7 having a single lbiasing means which returns said operating means to original position on release of manual pressure after pushing or turning.

9. An electric switch as claimed in claim 1 having means to prevent rotation of said operating means when the latter is pushed.

10. An electric switch as claimed in claim 1 having means on said contact-operating means to cause said first contact disengagement either upon rotary or rectilinear movement of said operating means, a boss, and means abutting the side of said boss after said operating means is depressed to prevent rotation of said operating means, said boss lying in the path of said abutting means after rotation of said operating means, thereby preventing rectilinear operation after such rotation.

11. An electric switch as claimed in claim 1 in which said operating means includes cam means and a movable pin engaged by said cam means to move said bridging contact means through said fractional distance.

12. An electric switch as claimed in claim 1 having means on said contact-operating means to cause said first contact disengagement either upon rotary or rectilinear movement of said operating means, said operating means including a boss and a member slid able in said boss, cam means operating said slidable member to operate said bridging contact means, and means abutting the side of said boss after said operating means is depressed to prevent rotation of said operating means, said boss lying in the path of said abutting means after rotation of said operating means,'thereby preventing rectilinear operation after such rotation.

13. The combination of signal means with an electric switch having a pair of contacts one of which is connected to a power line through said signal means, a second pair of contacts one of which is connected to the other contact of said first pair and to a translating device, the other contact of said'second pair being connected to another power line, bridging contact means in one position connecting said first pair of contacts and movable to a second position to connect said second pair of contacts, rotatable means to cause separation of said bridging contact means from said other contact of said first pair and to connect said bridging contact means with said other contact of said second pair for testing said signal means.

14. The combination of claim 13 for signal-means testing having means to prevent movement of said bridging contact means into said second position during said testmg.

15. The combination of claim 13 for signal-means testing having means to prevent said testing while said bridging contact means is in said second position.

16. The combination claimed in claim 13 for signalmeans testing having means to prevent movement of said bridging contact means into said second position during said testing, and means to prevent said testing while said bridging contact means is in said second position.

17. The combination of an electromagnetic contactor having a holding coil and holding contacts, with signal means, and with an electric switch having a pair of contacts one of which is connected to a power line through said signal means, a second pair of contacts one of which is connected to the other contact of said first pair and to said power line through said holding coil, the other contact of said second pair being connected to another power line, said holding contacts being connected in parallel with said second pair of switch contacts, bridging contact means in one position connecting said first pair of contacts and movable to a second position to connect said second pair of contacts, rotatable means tocause separation of said bridging contact means from said other contact of said first pair and to connect said bridging contact means with said other contact of said second pair for testing said signal means.

18. The combination of an electric switch and a pilot light, comprising a push button within which said pilot light is mounted, means mounting said push button for pushing or turning, means for testing said pilot light by turning said button, fixed switch contacts, and bridging contact means adapted to disengage and engage certain of said fixed contacts when pushed and retracted, and means to prevent turning of said button while said button is depressed.

19. The combination claimed in claim 18 having means to prevent depression of said button while turned for testing.

20. The combination of an electric switch with a pilot light comprising a push button within which said pilot light is mounted, means mounting said push button for pushing or turning, means for testing said pilot light by turning said button, fixed switch contacts, bridging contact .means adapted to disengage and engage certain of said fixed contacts when pushed and retracted, and means to I prevent depression of said button While turned for testing.

.position bridging said second pair, means to cause said bridging-contact means to disengage one of said first pair of fixed contacts on fractional movement ofsaid bridging 1 contact means from said first position to said second position, said bridging-contact means including an auxiliary contact which engages one contact of said second pair during said fractional movement while said bridgingcontact means remains engaged with the other fixed contact of said first pair and until the bridging-constact means engages the second contact of said second pair, on return movement of said operating means toward said first position said disengaging means acting to maintain said auxiliary contact in engagement with said one contact of the second pair after the bridgingcontact means has disengaged the second contact of the second pair.

22. An electric switch as claimed in claim 21 wherein the auxiliary member comprises a flexible lever connected at one end to said bridging-contact means.

References Cited in the file of this patent UNITED STATES PATENTS 

